Cryptographic technology is always a highly sensitive dual-use technology. All nations have to face
a dilemma in terms of password usage: on the one hand, to fully guarantee the safety and confidentiality of
personal communication, as well as personal privacy and communication freedom required by law; on the other
hand, to make sure law-enforcing departments and security organs crack down and prevent crime. It might be
a great help for crime and terrorist organizations that the wide application of cryptography is made public.
Many people believe that plain text communicated through the public network is accessible to an appropriate
government agency if law permits. Therefore, it has become a continuous hot issue of cryptographic technology
that how to design a cryptographic system through which legal persons are able to protect the safety of their
information, yet being monitored by government in the range permitted by law. In this study, an in-depth study
is carried out on the controversial key escrow technology, analyzing its composition and algorithm and pointing
out possible attacks and preventive measures.